The present invention relates to a fastener design, particularly to a self-drilling wall anchor device.

Referring to Figs. 1 and 2, a conventional self-drilling wall anchor comprises a threaded member 11, an outer sleeve 12 penetrated by the threaded member 11, and a drill element 13 connected to the threaded member 11. Wherein, the threaded member 11 is made of metal and comprised of a shank 111, a head 112 disposed at one end of the shank 111, an engaging part 113 disposed at the other end of the shank 111, and a threaded section 114 spirally disposed on the shank 111. Herein, the threaded section 114 has a first diameter a1 larger than a second diameter a2 of the engaging part 113.

The outer sleeve 12 is made of plastic and allows the threaded member 11 to penetrate therethrough. The outer sleeve 12 has a body 121, a through hole 122 defined in the body 121, a threaded portion 123 disposed on the body 121, and an arm section 124 disposed on the body 121, opposite to the threaded portion 123. Wherein, the body 121 has a first end 1211 and a second end 1212 defined thereon. The first end 1211 and the second end 1212 are communicated with the through hole 122, the threaded portion 123 is disposed near the second end 1212, and a peripheral flange 1231 is formed on the second end 1212. A plurality of slots 1241 are defined on the arm section 124. Moreover, the through hole 122 has a first area 1221 adjacent to the first end 1211 and a second area 1222 connected to the first area 1221 and adjacent to the second end 1212. The second area 1222 has a second area diameter b2 that is larger than a first area diameter b1 of the first area 1221. Whereby, when the threaded member 11 enters the through hole 122, the first area 1221 accommodates the engaging part 113, and the second area 1222 accommodates the threaded section 114. Additionally, the second area diameter b2 is larger than the first diameter a1, and the first diameter a1 is larger than the first area diameter b1.

The drill element 13 is made of metal. The drill element 13 has a drilling member 131 and a bore 132 disposed opposite to the drilling member 131 for connecting the engaging part 113. When the threaded member 11 enters the through hole 122 of the outer sleeve 12, the threaded section 114 is accommodated in the first area 1221, and the engaging part 113 is applied to protrude out of the first end 1211 for combining with the drill element 13. Thereby, the assemblage of the self-drilling wall anchor device 1 is complete.

Referring to Figs. 2 and 3, in using, the drill element 13 is set against a gypsum object 2 for drilling. Thereafter, the threaded member 11 brings the outer sleeve 12 into the gypsum object 2 by screwing. At the time the peripheral flange 1231 touches the gypsum object 2, the threaded member 11 keeps screwing and rotating to allow the arm section 124 to start deforming and twisting. When the arm section 124 achieves their extreme deformation and twisting, the threaded member 11 stops rotating to complete the screwing step and position the threaded member 11 on the object.

In practice, the second area diameter b2 of the outer sleeve 12 is larger than the first diameter a1 of the threaded section 114, so an interstice is incurred between the threaded section 114 and the second area 1222. While the threaded member 11 keeps screwing and the arm section 124 continues deforming and twisting, the threaded section 114 can not block the second area 1222 thoroughly. In this manner, the deformed and twisted arm section 124 is easily pulled or retracted into the interstice between the threaded section 114 and the second area 1222, which even forces and breaks a part of the gypsum object 2 and causes the fixed self-drilling wall anchor device 1 to only grip the remains of the gypsum object 2 that is not broken. Moreover, the twisted and deformed arm section 124 is simply propped by the peripheral flange 1231. Therefore, the anchor device 1 can not provide a satisfactory gripping effect since it might easily retract.

It is therefore the purpose of this invention to provide a self-drilling wall anchor device that does not over-twist or break gypsum objects while a fastening effect and an anti-pulling or anti-retracting effect are enhanced.

The self-drilling wall anchor device in accordance with the present invention comprises:

• a threaded member having a shank, a head disposed at one end of the shank, an engaging part disposed at the other end of the shank, and a first threaded section as well as a second threaded section spirally disposed on the shank, between the head and the engaging part. Wherein, a first diameter of the first threaded section is different from a second diameter of the second threaded section;
• an outer sleeve which is made of plastic for allowing the threaded member to penetrate. The outer sleeve has a body, a through hole defined in the body, a threaded portion disposed on the body, and an arm section disposed on the body, opposite to the threaded portion. Wherein, the body has a first end and a second end defined thereon. The first end and the second end are communicated with the through hole in which a first area with a first area diameter is formed adjacent to the first end, a second area with a second area diameter is connected to the first area, and a third area with a third area diameter is connected to the second area and disposed near the second end. The second area diameter is larger than the first diameter of the first threaded section but smaller than the second diameter of the second threaded section, and the third area diameter is larger than the second diameter of the second threaded section. The threaded portion is disposed near the second end. A peripheral flange, preferably having an outer diameter larger than a main diameter of the body, is formed between the threaded portion and the second end. A plurality of slots are defined on the arm section; and
• a drill element having a drilling member and a bore disposed opposite to the drilling member for combining with the engaging part.

Preferably, the first diameter of the first threaded section is smaller than the second diameter of the second threaded section, and the first diameter of the first threaded section is larger than a third diameter of the engaging part; the third area diameter of the third area is larger than the second area diameter of the second area, and the second area diameter is larger than the first area diameter.

Accordingly, the cooperation of the threaded member and the outer sleeve allows the second threaded section to block between the second area and the third area. Thereby, the outer sleeve is able to enter the gypsum object via the threaded member. Thereafter, when the peripheral flange touches a gypsum object, the arm section of the outer sleeve starts deforming and twisting. Preferably, the deformed and twisted arm section stays out of the gypsum object without being pulled into the gypsum object. Therefore, the self-drilling wall anchor device provides a favorable gripping effect and an anti-retracting performance.

Fig. 1 i

s a schematic view showing a conventional self-drilling wall anchor device;

Fig. 2

is a schematic view showing the conventional self-drilling wall anchor device in using;

Fig. 3

is a further schematic view showing the conventional self-drilling wall anchor device in using;

Fig. 4

is an exploded view showing a first preferred embodiment of the present invention;

Fig. 5

is a schematic view showing the first preferred embodiment of the present invention in using; and

Fig. 6

is a further schematic view showing the first preferred embodiment of the present invention in using.

The advantages of the present invention will become apparent to those of ordinary skilled in the art upon reading the following descriptions in conjunction with the accompanying drawings.

Referring to Figs. 4 and 5, a first preferred embodiment of the present invention is shown. A self-drilling wall anchor device 4 comprises a threaded member 41, an outer sleeve 42 accepting a penetration of the threaded member 41, and a drill element 43 connected to the threaded member 41. The threaded member 41 is made of metal and has a shank 411, a head 412 disposed at one end of the shank 411, an engaging part 413 disposed at the other end of the shank 411, and a first threaded section 414 as well as a second threaded section 415 spirally disposed on the shank 411, between the head 412 and the engaging part 413. Wherein, the first threaded section 414 and the second threaded section 415 have different diameters. In this embodiment, a first diameter A1 of the first threaded section 414 is smaller than a second diameter A2 of the second threaded section 415, and the first diameter A1 of the first threaded section 414 is larger than a third diameter A3 of the engaging part 413.

The outer sleeve 42 is made of plastic and has a body 421, a through hole 422 defined in the body 421, a threaded portion 423 disposed on the body 421, and an arm section 424 disposed on the body 421, opposite to the threaded portion 423. Wherein, the body 421 has a first end 4211 and a second end 4212 defined thereon, the first end 4211 and the second end 4212 are communicated with the through hole 422 in which a first area 4221 is formed adjacent to the first end 4211, a second area 4222 is connected to the first area 4221, and a third area 4223 is connected to the second area 4222 and disposed near the second end 4212. Wherein, the first area 4221, the second area 4222, and the third area 4223 have different diameters B1,B2,B3. In this embodiment, a third area diameter B3 of the third area 4223 is larger than a second area diameter B2 of the second area 4222, and the second area diameter B2 is larger than a first area diameter B1 of the first area 4221. Accordingly, when the threaded member 41 enters the through hole 422, the first area 4221 accommodates the engaging part 413, and the second area 4222 accommodates the first threaded section 414. The second area diameter B2 is further larger than the first diameter A1 of the first threaded section 414 but smaller than the second diameter A2 of the second threaded section 415, and the third area diameter B3 is larger than the second diameter A2 of the second threaded section 415. The threaded portion 423 is disposed near the second end 4212, and a peripheral flange 4231 is formed between the threaded portion 423 and the second end 4212. Preferably, the peripheral flange 4231 has an outer diameter larger than a main diameter of the body 421, and a plurality of slots 4241 are defined on the arm section 424.

Further, the drill element 43 is made of metal and has a drilling member 431 and a bore 432 disposed opposite to the drilling member 431 for combining with the engaging part 413, whereby the threaded member 41 and the outer sleeve 42 are assembled as a whole.

Referring to Fig. 5, in using, the drill element 43 is set against a gypsum object 5 for drilling. Herein, the threaded member 41 brings the outer sleeve 42 into the gypsum object 5 by screwing. When the peripheral flange 4231 touches the gypsum object 5, the threaded member 41 keeps rotating and the arm section 424 starts to deform and twist. When the deformation and the twisting of the arm section 424 reaches an extreme, the arm section 424 stops deforming and twisting to complete the screwing of the threaded member 41 and allow the threaded member 41 to be firmly fixed. Due to the second area diameter B2 on the outer sleeve 42 larger than the first diameter A1 but smaller than the second diameter A2 and the third area diameter B3 larger than the second diameter A2, the second threaded section 415 is able to block between the second area 4222 and the third area 4223. Therefore, there is no interstice incurred between the second threaded section 415 and the second area 4222. Whereby, the deformed and twisted arm section 424 stays out of the gypsum object 5 without being pulled into the interstice between the second threaded section 415 and the second area 4222 or into the gypsum object 5 as arrowed in Fig. 6. Consequently, the gypsum object 5 prop against the device 4 efficiently by keeping the peripheral flange 4231 and the deformed arm section 424 out. Therefore, the gripping effect of the self-drilling wall anchor device 4 is enhanced and the anti-pulling capability thereof is increased to prevent it from retracting easily.

To sum up, the present invention in particularly utilizes the threaded member having the first threaded section and the second threaded section that provide different diameters and the through hole in the outer sleeve having the connected first area, a second area, and a third area that also provide different diameters to enhance the fastening effect. In view of afore different diameters, when the threaded member cooperates with the outer sleeve to execute screwing, and the second threaded section blocks between the second area and the third area. Accordingly, the arm section deforms and twists out of the gypsum object, instead of being pulled into the gypsum object, which largely enhances the gripping effect and promotes an anti-pulling capability..

While we have shown and described the embodiment in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention.